MEG

The new CUBRIC MEG will use the same CTF 275 axial gradiometer design that we are currently using within CUBRIC. This system combines physical first-order axial gradiometers with effective third-order noise cancellation delivered by a reference SQUID array in the dewar. We have found this system to be a robust and stable platform for studying human brain activity, with a particular emphasis on cortical oscillatory dynamics in health and disease. This has resulted in several successful publications and grant awards for research projects studying both healthy brain function and diseases such as Epilepsy, Schizophrenia and Alzheimer’s.

In the new building, the core sensor array will be completely refurbished and upgraded with a new set of processing and acquisition electronics and we will install a larger magnetically shielded room (5m x 4 m).
This larger MSR will make it easier to study both challenging patient populations and drug manipulations that require careful physiological monitoring during the experiment. Coupled to the adjacent clinical research facility within the new building, this will make the CUBRIC MEG lab an optimised environment for clinical and pharmacological studies of the brain’s oscillatory dynamics.

In order to minimise the cost of running the MEG lab and to safeguard operation in the next few years, we will also install a new re-liquifier system that will capture helium gas normally lost to the atmosphere and re-liquefy it for use in the MEG system.

What is MEG?

Electrical activity within the brain generates magnetic fields that can be measured outside the using a technique known as magnetoencephalography (MEG). MEG recordings of an individual can be made while they are at rest, or performing a task, or undergoing a medical intervention such as treatment with a specific drug. The magnetic fields produced by the brain are extremely weak (around a billion times weaker than the magnetic field of a typical fridge magnet!) and require extremely sensitive measurement devices to be detected. MEG systems use special sensors called SQUIDs (Superconducting Quantum Interference Devices), which are sensitive enough to pick up minute differences in magnetic fields. These sensors only work at temperatures below -269°C, and so are constantly bathed In liquid helium in order to keep them cold enough to operate. As well as measuring magnetic fields generated by the brain, SQUIDS are so sensitive that they can pick up fields from the surrounding environment even if they are weak or at a distance. For this reason, our MEG is housed within a specially shielded room that blocks out outside magnetic ‘noise’. The image below shows the inside of the magnetically-shielded room (MSR) at CUBRIC during an MEG recording. The sensors and the liquid helium are held within the white unit above the participant’s head. From here the sensors measure the magnetic field while the participant responds to the images shown on the screen. These magnetic fields then provide information about the participant’s brain activity during the task.

CUBRIC, Cardiff University Brain Research Imaging Centre

The Cardiff University Brain Research Imaging Centre (CUBRIC) is a University facility operated and supported by the School of Psychology.